16 research outputs found

    Threat of allergenic airborne grass pollen in Szczecin, NW Poland: the dynamics of pollen seasons, effect of meteorological variables and air pollution

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    The dynamics of Poaceae pollen season, in particularly that of the Secale genus, in Szczecin (western Poland) 2004–2008 was analysed to establish a relationship between the meteorological variables, air pollution and the pollen count of the taxa studied. Consecutive phases during the pollen season were defined for each taxon (1, 2.5, 5, 25, 50, 75, 95, 97.5, 99% of annual total), and duration of the season was determined using the 98% method. On the basis of this analysis, the temporary differences in the dynamics of the seasons were most evident for Secale in 2005 and 2006 with the longest main pollen season (90% total pollen). The pollen season of Poaceae started the earliest in 2007, when thermal conditions were the most favourable. Correlation analysis with meteorological factors demonstrated that the relative humidity, mean and maximum air temperature, and rainfall were the factors influencing the average daily pollen concentrations in the atmosphere; also, the presence of air pollutants such as ozone, PM10 and SO2 was statistically related to the pollen count in the air. However, multiple regression models explained little part of the total variance. Atmospheric pollution induces aggravation of symptoms of grass pollen allergy

    Measurement of CP observables in B0 -> D K*0 with D -> K+ K-

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    The decay B0 -> D K*0 and the charge conjugate mode are studied using 1.0fb-1 of pp collision data collected by the LHCb experiment at sqrt(s) = 7TeV in 2011. The CP asymmetry between the B0 -> D K*0 and the B0bar -> D K*0bar decay rates, with the neutral D meson in the CP-even final state K+K-, is found to be A_d_KK = -0.45 +- 0.23 +- 0.02, where the first uncertainty is statistical and the second is systematic. In addition, favoured B0 -> D K*0 decays are reconstructed with the D meson in the non-CP eigenstate K+ pi-. The ratio of the B-flavour averaged decay rates in D decays to CP and non-CP eigenstates is measured to be R_d_KK = 1.36 (+0.37) (-0.32) +- 0.07, where the ratio of the branching fractions of D0 -> K- pi+ to D0 -> K+ K- decays is included as multiplicative factor. The CP asymmetries measured with two control channels, the favoured B0 -> DK*0 decay with D -> K+ pi- and the Bs0bar -> D K*0 decay with D K+ K-, are also reported

    First observation of the decay Bs0φKˉ0B_s^0 \rightarrow φ\bar{K}^{*0}

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    The first observation of the decay Bs0ϕKˉ0B_s^0 \rightarrow \phi \bar{K}^{*0} is reported. The analysis is based on a data sample corresponding to an integrated luminosity of 1.0 fb1^{-1} of pppp collisions at s=7TeV\sqrt{s} = 7 TeV, collected with the LHCb detector. A yield of 30±630 \pm 6 Bs0(K+K)(Kπ+)B_s^0 \rightarrow (K^+K^-)(K^-\pi^+) decays is found in the mass windows 1012.5 < M(K^+K^-) < 1026.5 MeV/c^2 and 746 < M(K^-\pi^+)< 1046 MeV/c^2. The signal yield is found to be dominated by Bs0ϕKˉ0B_s^0 \rightarrow \phi \bar{K}^{*0} decays, and the corresponding branching fraction is measured to be B(Bs0ϕKˉ0)=(1.10±0.24(stat)±0.14(syst)±0.08(fd/fs))×106{\cal B}(B_s^0 \rightarrow \phi \bar{K}^{*0}) = (1.10 \pm 0.24 (stat) \pm 0.14 (syst) \pm 0.08 (f_d/f_s)) \times 10^{-6}, where the uncertainties are statistical, systematic and from the ratio of fragmentation fractions fd/fsf_d/f_s which accounts for the different production rate of B0B^0 and Bs0B_s^0 mesons. The significance of Bs0ϕKˉ0B_s^0 \rightarrow \phi \bar{K}^{*0} signal is 6.1 standard deviations. The fraction of longitudinal polarization in Bs0ϕKˉ0B_s^0 \rightarrow \phi \bar{K}^{*0} decays is found to be f0=0.51±0.15(stat)±0.07(syst)f_0 = 0.51 \pm 0.15 (stat) \pm 0.07 (syst)

    Measurement of Upsilon production in pp collisions at sqrt{s}=2.76 TeV

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    The production of Upsilon(1S), Upsilon(2S) and Upsilon(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb^{-1} collected in proton-proton collisions at a centre-of-mass energy of sqrt{s}=2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the Upsilon transverse momentum and rapidity, over the ranges p_T&lt;15 GeV/c and 2.0 Upsilon(1S) X) x B(Upsilon(1S) -&gt; mu+mu-) = 1.111 +/- 0.043 +/- 0.044 nb, sigma(pp -&gt; Upsilon(2S) X) x B(Upsilon(2S) -&gt; mu+mu-) = 0.264 +/- 0.023 +/- 0.011 nb, sigma(pp -&gt; Upsilon(3S) X) x B(Upsilon(3S) -&gt; mu+mu-) = 0.159 +/- 0.020 +/- 0.007 nb, where the first uncertainty is statistical and the second systematic.</y<4.5.

    Study of beauty hadron decays into pairs of charm hadrons

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    First observations of the decays Λb0Λc+D(s)\Lambda_b^0 \to \Lambda_c^+ D_{(s)}^- are reported using data corresponding to an integrated luminosity of 3fb13\,{\rm fb}^{-1} collected at 7 and 8 TeV center-of-mass energy in proton-proton collisions with the LHCb detector. In addition, the most precise measurement of the branching fraction B(Bs0D+Ds){\mathcal{B}(B_s^0 \to D^+D_s^-)} is made and a search is performed for the decays B(s)0Λc+ΛcB^0_{(s)} \to \Lambda_c^+ \Lambda_c^-. The results obtained are \begin{eqnarray*} \mathcal{B}(\Lambda_b^0 \to \Lambda_c^+ D^-)/\mathcal{B}(\Lambda_b^0 \to \Lambda_c^+ D_{s}^-) and=and 0.042 \pm 0.003({\rm stat}) \pm 0.003({\rm syst}), \left[\frac{\mathcal{B}(\Lambda_b^0 \to \Lambda_c^+ D_{s}^-)}{\mathcal{B}({\kern 0.2em}\overline{\kern -0.2em B}_d^0 \to D^+D_s^-)}\right]\big/\left[\frac{\mathcal{B}(\Lambda_b^0 \to \Lambda_c^+\pi^-)}{\mathcal{B}({\kern 0.2em}\overline{\kern -0.2em B}_d^0 \to D^+\pi^-)}\right] and=and 0.96 \pm 0.02({\rm stat}) \pm 0.06({\rm syst}), \mathcal{B}(B_s^0 \to D^+D_s^-)/\mathcal{B}({\kern 0.2em}\overline{\kern -0.2em B}_d^0 \to D^+D_s^-) and=and 0.038\pm0.004({\rm stat})\pm0.003({\rm syst}), \mathcal{B}({\kern 0.2em}\overline{\kern -0.2em B}^0 \to \Lambda_c^+ \Lambda_c^-)/\mathcal{B}({\kern 0.2em}\overline{\kern -0.2em B}_d^0 \to D^+D_s^-) and &lt; and 0.0022\; [95\% \; {\rm C.L.}], \mathcal{B}(B^0_{s} \to \Lambda_c^+ \Lambda_c^-)/\mathcal{B}(B_s^0 \to D^+D_s^-) and &lt; and 0.30\; [95\% \; {\rm C.L.}]. \end{eqnarray*} Measurement of the mass of the Λb0\Lambda_b^0 baryon relative to the B0B^0 meson gives M(Λb0)M(B0)=339.72±0.24(stat)±0.18(syst){M(\Lambda_b^0) -M(B^0) = 339.72\pm 0.24({\rm stat}) \pm 0.18({\rm syst})} MeV/c2/c^2. This result provides the most precise measurement of the mass of the Λb0\Lambda_b^0 baryon to date

    Precision measurement of the ratio of the Λb0Λ^0_b to B0\overline{B}^0 lifetimes

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    The LHCb measurement of the lifetime ratio of the Λb0\Lambda^0_b to the B0\overline{B}^0 meson is updated using data corresponding to an integrated luminosity of 3.0 fb1^{-1} collected using 7 and 8 TeV centre-of-mass energy pppp collisions at the LHC. The decay modes used are B0J/ψpK\overline{B}^0\to J/\psi p K^- and B0J/ψπ+K\overline{B}^0\to J/\psi \pi^+ K^-, where the π+K\pi^+K^- mass is consistent with that of the K0(892)\overline{K}^{*0}(892) meson. The lifetime ratio is determined with unprecedented precision to be 0.974±0.006±0.0040.974\pm0.006\pm0.004, where the first uncertainty is statistical and the second systematic. This result is in agreement with original theoretical predictions based on the heavy quark expansion. Using the current world average of the B0\overline{B}^0 lifetime, the Λb0\Lambda^0_b lifetime is found to be 1.479±0.009±0.0101.479 \pm 0.009 \pm 0.010 ps

    Measurement of the branching fractions of the decays Bs -&gt; D0bar K- π+ and B0 -&gt; D0bar K+ π-

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    The first observation of the decay Bs -&gt; D0bar K- {\pi}+ is reported. The analysis is based on a data sample, corresponding to an integrated luminosity of 1.0 fb-1 of pp collisions, collected with the LHCb detector. The branching fraction relative to that of the topologically similar decay B0 -&gt; D0bar {\pi}+ {\pi}- is measured to be BR(Bs -&gt; D0bar K- {\pi}+)/BR(B0 -&gt; D0bar {\pi}+ {\pi}-) = 1.18 +- 0.05 (stat.) +- 0.12 (syst.). In addition, the relative branching fraction of the decay B0 -&gt; D0bar K+ {\pi}- is measured to be BR(B0 -&gt; D0bar K+ {\pi}-)/BR(B0 -&gt; D0bar {\pi}+ {\pi}-) = 0.106 +- 0.007 (stat.) +- 0.008 (syst.)

    Measurements of the B+B^+, B0B^0, Bs0B_s^0 meson and Λb0Λ_b^0 baryon lifetimes

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    Measurements of bb-hadron lifetimes are reported using pppp collision data, corresponding to an integrated luminosity of 1.0fb1^{-1}, collected by the LHCb detector at a centre-of-mass energy of 77Tev. Using the exclusive decays B+J/ψK+B^+\to J/\psi K^+, B0J/ψK(892)0B^0\to J/\psi K^*(892)^0, B0J/ψKS0B^0\to J/\psi K^0_{\rm S}, Λb0J/ψΛ\Lambda_b^0\to J/\psi \Lambda and Bs0J/ψϕB^0_s\to J/\psi \phi the average decay times in these modes are measured to be τB+J/ψK+\tau_{B^+\to J/\psi K^+} = 1.637±1.637 \pm 0.004 ±\pm 0.003 ps, τB0J/ψK(892)0\tau_{B^0\to J/\psi K^*(892)^0} = 1.524±1.524 \pm 0.006 ±\pm 0.004 ps, τB0J/ψKS0\tau_{B^0\to J/\psi K^0_{\rm S}} = 1.499±1.499 \pm 0.013 ±\pm 0.005 ps, τΛb0J/ψΛ\tau_{\Lambda_b^0\to J/\psi \Lambda} = 1.415±1.415 \pm 0.027 ±\pm 0.006 ps and τBs0J/ψϕ\tau_{B^0_s\to J/\psi \phi} = 1.480±1.480 \pm 0.011 ±\pm 0.005 ps, where the first uncertainty is statistical and the second is systematic. These represent the most precise lifetime measurements in these decay modes. In addition, ratios of these lifetimes, and the ratio of the decay-width difference, ΔΓd\Delta\Gamma_d, to the average width, Γd\Gamma_d, in the B0B^0 system, ΔΓd/Γd=0.044±0.025±0.011\Delta \Gamma_d/\Gamma_d = -0.044 \pm 0.025 \pm 0.011, are reported. All quantities are found to be consistent with Standard Model expectations

    Search for CP violation in D+ -&gt; phi pi+ and Ds+ -&gt; Ks pi+ decays

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    A search for CP violation in D+ -&gt; phi pi+ decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb^{-1} at a centre of mass energy of 7 TeV. The CP-violating asymmetry is measured to be (-0.04+/-0.14+/-0.14)% for candidates with K-K+ mass within 20 MeV/c^{2} of the phi meson mass. A search for a CP-violating asymmetry that varies across the phi mass region of the D+ -&gt; K-K+pi+ Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the Ds+ -&gt; Ks pi+ decay is measured to be (0.61+/-0.83+/-0.14)%

    First observation of Bs -&gt; J/psi f0(980) decays

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    Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the hadronic decay Bs -&gt; J/psi f0(980) is observed. This CP eigenstate mode could be used to measure mixing-induced CP violation in the B_s system. Using a fit to the pi+ pi- mass spectrum with interfering resonances gives R_{f0/phi} = [Gamma(Bs -&gt; J/psi f0, f0 -&gt; pi+ pi-)]/[Gamma(Bs -&gt; J/psi phi, phi -&gt; K+K-)] = 0.252^{+0.046+0.027}_{-0.032-0.033}, where the uncertainties are statistical and systematic, respectively
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